Centrifugal separators useful in separating entrained material, including oil, from gases generated by an internal combustion engine are sometimes configured so that a housing defines a separation chamber into which a centrifuge rotor is positioned. The rotor is typically mounted for rotation in bearings supported by the housing and is driven by a suitable drive coupled to a shaft portion of the rotor that extends through one of the bearings and out of the separation chamber. During operation, oil separated from the gas must be drained from the separation chamber.
A typical centrifugal separator useful for cleaning gas generated by an internal combustion engine, such as crankcase gas, is shown in FIG. 1 and is generally designated by the reference number 10. The centrifugal separator 10 includes a stationary housing 12 that defines an interior separation chamber 14. A rotor generally designated by the reference number 16 is positioned in the interior area and includes a drive shaft 18 rotatably mounted in upper bearing 20 and lower bearing 22. The drive shaft 18 extends through the lower bearing 22 into a drainage chamber 24. A turbine 26 is positioned in the drainage chamber 24 and is mounted on the drive shaft 18 for rotation therewith. During operation of the centrifugal separator 10, the turbine 26 and thereby the rotor 18 is caused to rotate by a stream of fluid generally indicated by the arrows labeled “A” directed under pressure against the turbine. The liquid used to cause the turbine 26 to rotate is typically oil, either pressurized by the internal combustion engine or another pressure source. The oil, after impinging upon the turbine, exits the drainage chamber 24 through an outlet 28.
A partition wall 30 separates the separation chamber 14 from the drainage chamber 24. An aperture 32 extends through the partition wall 30 near the periphery of the partition wall and opens into a stepped bore 34 defined by a drainage housing 36 in communication with the outlet 28.
During operation, gas generated by the internal combustion engine and generally designated by the reference character “B” enters the separation chamber through apertures 38 and into a stack of rotating separation discs 40. Entrained material is separated from the gas in the separation discs 40 and is thrown from the edges of the discs against an inner wall of the housing 14. This separated material will in all likelihood include oil.
The cleaned gas exits the centrifugal separator via outlet 42, while the oil and other separated material travels down the inner wall 44 and into passage 46. The oil then passes through a first aperture 48 onto the partition wall and through the aperture 32 into the stepped bore 34 and out of the outlet 28.
A difficulty that occurs with the above-described centrifugal separator is that because these devices are used in connection with internal combustion engines, it is possible for the centrifuge to assume different orientations whether due to mounting constraints or, if used in a vehicle, the different attitudes a vehicle may assume during driving. Depending on the degree of incline of the centrifugal separator, there is a potential for separated material such as oil to leak into the cleaned gas and be discharged from the clean gas outlet, thereby defeating the purpose of the centrifugal separator. Another potential problem associated with centrifugal separators configured as described above is that the operation of the turbine and the driving oil being forced there against can cause the driving oil to leak into the separation chamber through the bore 34 and contaminate the cleaned gas, again defeating the purpose of the centrifugal separator. Moreover, the above-described centrifugal separator requires that there be more than one passage/outlet for the egress of oil.
Based on the foregoing, it is the general object of the present invention to provide a centrifugal separator that improves upon or overcomes the problems and drawbacks associated with prior art devices.